1. Field of the Invention
The invention relates generally to apparatus, systems, and methods for separating particulate matter and solids from a fluid. More particularly, the invention relates to cyclonic separators and method of using same to separate particulate matter and solids from well fluids in a downhole environment.
2. Background of the Technology
Geological structures that yield gas typically produce water and other liquids that accumulate at the bottom of the wellbore. Typically, the liquids comprise hydrocarbon condensate (e.g., relatively light gravity oil) and interstitial water in the reservoir. The liquids accumulate in the wellbore in two ways as single phase liquids that migrate into the wellbore from the surrounding reservoir, and as condensing liquids that fall back into the wellbore during production. The condensing liquids actually enter the wellbore as vapors, however, as they travel up the wellbore, their temperatures drop below their respective dew points and they phase change into liquid condensate.
In some hydrocarbon producing wells that produce both as and liquid, the formation gas pressure and volumetric flow rate are sufficient to lift the liquids to the surface. In such wells, accumulation of liquids in the wellbore generally does not hinder gas production. However, in wells where the gas phase does not provide sufficient transport energy to lift the liquids out of the well (i.e. the formation gas pressure and volumetric flow rate are not sufficient to lift the liquids to the surface), the liquid will accumulate in the well bore.
In many cases, the hydrocarbon well may initially produce gas with sufficient pressure and volumetric flow to lift produced liquids to the surface, however, over time, the produced gas pressure and volumetric flow rate decrease until they are no longer capable of lifting the produced liquids to the surface. Specifically, as the life of a natural gas well matures, reservoir pressures that drive gas production to surface decline, resulting in lower production. At some point, the gas velocities drop below the “Critical Velocity” (CV), which is the minimum velocity required to carry a droplet of water to the surface. As time progresses droplets of liquid accumulate in the bottom of the wellbore. The accumulation of liquids in the well impose an additional back-pressure on the formation that may begin to cover the gas producing portion of the formation, thereby restricting the flow of gas and detrimentally affecting the production capacity of the well. Once the liquids are no longer lifted to the surface with the produced gas, the well will eventually become “loaded” as the liquid hydrostatic head begins to overcome the lifting action of the gas flow, at which point the well is “killed” or “shuts itself in,” Thus, the accumulation of liquids such as water in a natural gas well tends to reduce the quantity of natural gas which can be produced from the well. Consequently, it may become necessary to use artificial lift techniques to remove the accumulated liquid from the wellbore to restore the flow of gas from the formation into the wellbore and ultimately to the surface. The process for removing such accumulated liquids from a wellbore is commonly referred to as “deliquification.”
In most cases, the accumulated liquids in the bottom of a wellbore include suspended particulate matter and solids. During downhole pumping and artificial lift operations, such solids add to the weight of the liquid that must be lifted to the surface, thereby increasing the demands placed on the lift equipment. Moreover, such solids are abrasive and may detrimentally wear components in the downhole lift equipment. Accordingly, there remains a need in the art for devices, systems, and methods for removing particulate matter and solids from accumulated downhole well liquids before lifting such liquids to the surface.